#lang racket

(define point 
  (cons 3
    (cons 4
      (cons 5 empty))))

(define (distance-to-0-for-3 point)
  (sqrt (add-up-sqr-list point))
  )

(define (add-up-sqr-list list)
  (cond 
    [(empty? (rest list)) (sqr (first list))]
    [else (+ (sqr (first list)) (add-up-sqr-list (rest list)))]
    )
  )

(distance-to-0-for-3 point)
